ML20126M838
| ML20126M838 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 06/08/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20126M832 | List: |
| References | |
| NUDOCS 8106220435 | |
| Download: ML20126M838 (4) | |
Text
' " va UNITED STATES
. // i NUCLEA.3 REGULATORY COM*.ilSSlON 3
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SAFETY EVALUATION SY THE OFFICE 0: NUCLEAR' REACTOR REGULATION AMENDMENT NO. 68 TO FACILITY OPERATING LICENSE NO. OPR-3 YANKEE NUCLEAR PCWER STATION (YANKEE-ROWE)
YANKEE ATCMIC ELECTRIC COMPANY DOCKET NO. 50-29 1.0 Introduction 22, 1980, Yankee Atomic Electri: C:noany (the 3y letter dated October licensee) recuested an amendment to Facility Cperating Licanse No. CPR-3 for Yankee Nuclear Power Station (Yankee-Rowe).
The amendment would defer Inservice Inspection and testing requirements for four dif ferent component types past the normal la month interval until tne c;mpletion of the 1981 refueling outage, which is scheduled to start May 2,1981, and end accroximately July 1,1981.
The following comoonents would be affected: reactor shroud tubes, oressurizer cladding, steam ;anara:or tubing, and low pressure safety injection puros.
2.0 Background
During 19EO, Yankee :we experienced a nine conth shutdown because of a failure of its main turbine generator.
This failure caused tne refueling t
Thers-outage originally scheduled for the Summer of 1930 to be del,ed.
fore, the reactor v.as not refueled during the nine-mentn turbine repair outage, but rather it was lef t in a cold shutdcwn condition with tne primary coolant boundary remaining intact.
Since the main coolant system has remained closed during the nine month outage, performance of certain inservice inspection and testing (scheduled to coincide with the refueling outage) would require an opening of the main coolant system and would significantly increase radiation exposure for workers performing these The licensee decided not to open the main coolant system solely tests.
to perform these inspections in order to minimize personnel radiation
- exposure, By letter dated Octcber 22, i^EO, the licensee recuested an trandrent o the c;eratir.g license for Yankee 07.ve Nuci sar Pl ant to defer this inservice inspection and testing until tne next refueling cutage, wnich commenced in May 1981.
The licensee has justified his recuest on the basis of Commission's policy to reduce radiation ex?csure to as reasonably achievable ( ALAF.A).
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'8106220 435 3.0 Steam Senerator Tube Ins:ections Discussion and Evaluation _
Yankee Rowe Nuclear Plant is the oldest licensed pressurized water reactor in the United States.
Since the beginning of power operation, steam generator inservice insoections at Yankee Rowe have been conducted about every 18 calendar months.
The cumulative number of tubes plugged to date This can be (over a 19 year period) is 113 in all four steam generators.
broken down to 43, 6, 21 and 43 plugged tubes in Steam Generators #1, #2,
- 3, and #4, respectively.
The last steam generator inservice inspection at Yankee Rowe was conducted in November of 1978.
Subsequent to the Novemoer 1978 inspection, Yankee Rowe was shutdown for three months in 1979 for TMI Lessons Learned and other related maintenance.
The results of the most recent inspection (Nevamber 197S) at V qkee 0 0ae Nuclear Station indicate that caustic stress corrosion continue to cccur at a rate consistent with that observed previously.
Seventeen tubes in Steam Generator #1 and 13 tubes in Steam Generator #4. sere. lugged The plugging implemented in Novemoer as a result of 100% inspection.
1978 and in previous inspections has proven successful in reccving from sarvice severely degraded tubes which are the most likely candidates to develop inservice leaks.
Degradations resulting in tube..all thinning and tube castriction activity (denting) remain low as compared. to.other similarly Therefore, it is our evaluation that the Novecter 1973 degraded uni.ts.
inspection results, implemented plugging, togat',er with the existing licensing conditions restricting steam generator oceration in the event that detectable leaks occur, provide adecuate supoort to the exist'og practice of allowing an 18 month operating interval.
Since restart in November 1978, 28 calendar months have gone by without steam generator inservice inspection at the Yankee Rowe Nuclear Plant.
However, of the 28 calendar montns, the plant was in a cold shutdown, depressurized condition for a total of 12 calendar months. Therefore, tne actual operating time for Yankee Rowe is only 16 calendar months.
By June 1981, the Yankee Rcwe Nuclear Piant will have completed approxi-mately 18 months of power operation.
Considering the facts that 18 calendar mcnths is a normal operating interval for the Yankee Rcwe Nuclear Plant and has been previously accepted by the NRC, continued operation of this unit until June 1981 without a steam generator inser-vice insoection will not alter our conclusion that the steam generator tu:es will maintain an acceatable degree cf ints;rity.
The above consideraticns together with the secon:ary sater chemistry control program, a program which has resulted in a small number of defective l
tubes during the plant's operating history, will provide reasonable assurance that the health and safety of tne public will be protected.
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. On this basis, and in keeping with the Commission's policy to reduce radiation exposure to levels as low as reasonably achievable ( ALARA),
we conclude that the steam generator tube inservice inspection may be deferred until July 1981 without undue hazard to the health and safety of the public.
4.0 Low Pressure Safety Infection (LPSI) Pumos Discussion and Evaluation Inservice ficw testing of the LPSI pump is usually performed during the refueling outage when the main coolant system is normally opened.
Surveillance, testing of the LPSI pump requires removal of the reactor head and hence opening of the main coolant system.
This would signifi-cantly increase radiation exposure to personnel performing these tests.
The ancunt of radiation would be in the range of 300 meem/hr-can and it takes approximately l'48 Tan-hcurs to complete the r21uired surveillance testing.
The licensee's commitment to ALAP.A philosophy requires that the radiation exposure to personnel be minimized, if practicable.
Since significant radiation exposure is involved during surveillance testing of the LPSI pump, the prooosed change to Yankee Rowe technical specifica-
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tions, as mentioned in Page 3/4 5-8 of Appendix A of the specifica; ion is acceptable, and we conclude that the inservice flow testing of the LPSI pumps may be deferred until July 1981 without undue hazard to the heaith and safety of the public.
5.0 Ra5ctor Intac9als and Pressurizar Cladding D'scussion 3rd Evaluation _
Section 4.4.9.2 and 4.4.9.3, respectively, of the Technical Specifications require certain reactor intervals and the pressurizer interior cladding be inspected for abnormalties and cracking.
These inscections are normally performed once per 18 months and are done at refueling outages because they require opening of the Reactor Vessel and Pressurizer.
Because Yankee Rowe was shutdown for nine months due to a turbine failure ahich did not af fect these components, because the primary system was cooled down and depressurized with no primary coolant flow, and because of the large radiation exposure required to perform these insoections, we feel that delaying the calendar timing of the inspections to coincide with the 1981 refueling outage is reasonable, and in accordance with the original intant of the Technical Specifications.
'4 9, therefore, conclude I
tnat tnis tasting may be deferred until July 1931.a 15:ut 1:ard to ;53 esi L rd safety of tna pualic.
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l l i 6.0 Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is ins:gnificant from the standpoint of environceqtal impact and, pursuant to 10 CFR iS1.5(d)(4), that an environmental impact state-ment or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
7.0 Conclusion We have concluded, based on the considerations discussed above, that: (1) cecause the amendment dces not involve a significant incralse in the pecbability or consecuences of accidents previously considered and dces not involve a significant decrease in a safety margin, the amendment dces not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be andangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with.tne Commission's regulations and the issuance of this amendment will not be inimical to the commen dafanse and security or to the health and safety of the public.
Cate:
June 3, 1931 i
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